Iowa fire officials have concluded the cause of a house fire in Fort Dodge that killed a woman and two young children cannot be determined.The Iowa Department of Public Safety said Thursday that the State Fire Marshal Division has ruled the source of the Feb. 22 fire as undetermined.Autopsy results revealed 25-year-old Amy Devlin, her 6-month-old son Bryce Devlin and 5-year-old Joseph Kennedy died of smoke inhalation from the fire.They were found in a second-story bedroom after the flames had been extinguished. Three others were transported to the hospital to undergo treatment for burns.Officials say the fire marshal and other agencies continue to investigate the fire. No further information has been released.

Iowa fire officials have concluded the cause of a house fire in Fort Dodge that killed a woman and two young children cannot be determined.

The Iowa Department of Public Safety said Thursday that the State Fire Marshal Division has ruled the source of the Feb. 22 fire as undetermined.